(216ag) Adhesion of Poly(acrylic acid) Hydrogel

A series of poly(acrylic acid) (PAA) hydrogels were synthesized by in-situ free radical polymerization of acrylic acid (AA) in the presence of cross-linker N, N ′-methylenebisacrylamide (BIS) in aqueous media. The rheological test was performed to investigate the effects of cross-linker BIS content on the modulus and viscosity of the resulting hydrogels, where a critical gel point was found during the transition from liquid to solid. As the cross-linker concentration increased, the effective elastic modulus were steady-state during a large range of strain and increased dramatically at low cross-linking densities. The influence of pH value and crosslinking density on the swelling ratio was studied. 180°peel strength test was used to study the adhesion of the synthesized hydrogels both in air and water. Furthermore, JKR indention tests were also performed to investigate effects of the cross-linking density on the adhesion and mechanical properties in terms of adhesive pull-off and Young modulus. PAA based hydrogels should be ideal candidate for bioadhesives.